Photonic circuits are useful as optical data links in applications such as, but not limited to, high performance computing (HPC), optical memory extension (pOME), datacenters (DC), and device interconnects. For example, in mobile computing platforms a photonic IC (PIC) is a useful means of I/O to rapidly update or sync a mobile device with a host device and/or cloud service where a wireless or electrical link has insufficient bandwidth. Such optical links utilize an optical I/O interface that includes an optical transmitter and an optical receiver.
Typically, a PIC will include many photonic components such as, but not limited to, laser light sources, photo detectors, and light modulators. While monolithic integration of PICs continues to evolve, integration of separate optical components offers advantageous component flexibility. Photonic components generally need to be electrically coupled to electrical integrated circuits (EICs), for example for driving of photonic components, and further optically coupled to each other to achieve a useful photonic circuit. PLCs entail an architecture in which at least the optical coupling of photonic components is provided by a planar substrate, such as a semiconductor wafer, that is fabricated in accordance with the many techniques employed in the manufacture of EICs.
As a PLC can enable a micron-scale integration of the photonic components, such architectures and techniques for manufacturing a PLC are important for reducing manufacturing costs associated with PICs and also for reducing the form factor of a PIC, both of which is needed to increase the adoption of optical I/O.